"Proposition 8 serves no purpose, and has no effect, other than to lessen the status and human dignity of gays and lesbians in California, and to officially reclassify their relationships and families as inferior to those of opposite-sex couples."

The Circuit Court backed up District Judge Judge Vaughn Walker, who ruled in 2010 that California has no "rational basis" to single out gays as ineligible for marriage.

The group fighting for Proposition 8, which passed in 2008 after thousands of gay couples had already married, appealed Walker's decision arguing that it should be vacated because Walker is gay and has a long-time same-sex partner.

That ruling was called a "grand slam" by gay rights advocates, who hope it will convince the U.S. Supreme Court to decide that states cannot outlaw gay marriage.

But today's ruling was explicit in that the court's decision is "narrow" and only relates to California, not the entire nation. The pro-Prop. 8 camp has said it will appeal.

In a separate decision, the court refused to invalidate Walker’s ruling on the grounds that he should have disclosed he was in a long term same-sex relationship.

The group can now ask that all 11 members of the 9th Circuit hear their case, instead of just the panel of three who decided against them on Tuesday.